Put her alongside The Incredibles in a tailored deck, keep her safe, and keep her questing, and youll be able to maximise her potential as a low-cost but highly efficient character card
Bear in mind as well that if your opponent doesnt find a way to deal with Jafar on their turn, which is definitely a risk with their hand of seven new cards, then you can just sing A Whole New World again if you drew it from the last one
Once the ability resolves, the bonus applied by that instance of the ability doesn't change even if the number of permanent cards in your graveyard changes
Sapphire/Steel has some really broken cards in it (Dig a Little Deeper) and actually has a coherent strategy that doesnt contradict itself
You can set this up in the first few turns with Queen first, Nick Wilde Sly Fox Sleuth and the Queen damage ability on turn two, into Pluto turn three to play Queen again, setting you up for something similar turn four
only an Amethyst/Steel card can be used